Method for detecting single nucleotide polymorphism in nucleic acid

A method for detecting a single nucleotide polymorphism in nucleic acids, characterized in that the method includes mixing (A) a nucleic acid probe comprising a nucleotide sequence complementarily hybridizable to an evaluation subject nucleic acid/an antisense strand thereof containing at least one single nucleotide polymorphism, and tagged with a nucleotide sequence of a hairpin structure having a bulge at a 5′-terminal thereof, wherein a guanine residue is introduced at an adjoining position of the bulge, and wherein a naphthyridine derivative compound is immobilized to the bulge; and (B) the evaluation subject nucleic acids; and detecting a signal ascribed to the naphthyridine derivative compound when the above nucleic acid probe and the above evaluation subject nucleic acids are hybridized, thereby evaluating the above single nucleotide polymorphism.